This invention relates to an interior core protector and, more particularly, to the protection of the interior material in a roll of coiled material, for example, a coil of sheet steel.
It is well known that sheet steel, e.g., that which is used extensively in the automobile industry, is placed in large coils by the steel producer for shipment to the user. These coils weigh upwards to 15 tons and include a center core or opening therethrough. It is quite common in strapping of the coil to prevent its uncoiling to place steel straps through the center core and about the outside of the coil. Typically, at least two and sometimes three or four of these straps spaced about the coil are used. Furthermore, it is quite common in the transport of these heavy coils, particularly in their loading and unloading from trucks and railway cars, to use a C-hook which comes down and passes through the center core and is then raised to engage the interior surface of the material to lift the coil on and off the truck or railway car. In doing so, the C-hook often damages the metal particularly by bending of the edges of the material located at the center of the coil. That is, when the C-hook is placed through the coil and raised upwardly into engagement with the material, it is rare that the hook ever engages the material at both edges with equal pressure. Rather, the hook typically first engages one edge and then the other. When this happens, the pressure of the hook on the material causes its bending. This bent material, of course, is not usable and must be scrapped. It is not uncommon for the user to have to scrap 30 to 50 feet of the sheet metal because of such damage.
In addition to damage by the C-hook in loading and unloading of the coil material, it is also quite common for the transporter to throw a chain through the interior core of the coil to secure the coil on a truck or railway car. This likewise causes damage to the edges of the material causing waste and scrap of what would otherwise be usable material.
Thus, there was a need for an interior core protector for positioning about the inner diameter of a roll of coiled material to protect the material from damage that was relatively economic to produce, that provided full protection for the material about the 360.degree. circumference of the interior core, and that provided advantages in terms of economic use of materials and economies of shipping to the customer.
In my U.S. Pat. No. 4,513,864, I provided an interior core protector including a pair of overlapping formed angular paperboard members which were manufactured in a flat, i.e., non-arcuate configuration. One leg of each of the members included a series of cuts spaced along its length and extending from the free edge of the leg to the angle joining the legs. These cuts permitted bending of the core protector to conform to the inner diameter of the coil. The cuts in the legs of one of the members was offset with respect to the cuts in the other member such that when the protector was bent to conform to the inner diameter of the coil and the spacing along each cut correspondingly increased, i.e., the cut opened up when the protector was bent, there was nevertheless provided a section of paperboard material overlapping each cut. The core protector thus provides protection for the material about the complete circumference of the inner core of the coil. Thus, when a chain was thrown through the core or a C-hook passing through the coil engaged the material, the edges of the inner length of the material were protected from damage. No special locating or positioning of the C-hook, for example, was needed. Rather, since 360.degree. protection to the edges of the material at the inner core was provided, the coil could be grasped at any location.
It has been found, however, that in some applications it is desirable to have a more rigid core protector which will more firmly seat in the core of the coil and not be subject to dislodging therefrom. Such a core protector in addition must offer the advantages of providing the coiled material with protection including protection to the edges of the inner length of material around the entire circumference of the core, economy of materials of construction, economic use of this material in that there is very little waste in forming the protector, and economies of packaging and shipping whereby the components of the core protector may be shipped merely by stacking up a series of protectors one on another and shipping them in a flat or non-arcuate configuration thus resulting in full utilization of shipping capacity with no waste of space.
To this end, the core protector of the present invention is adapted for positioning about the inner diameter of coiled material to protect the material from damage about its entire inner circumference, is relatively economic to produce, provides full protection for the material about the 360.degree. circumference of the core, provides advantages in terms of economic use of materials and economies of packaging and shipping to the customer, and is more rigid for placement and retention within the core of the coil.
In a presently preferred form of the invention, the interior core protector includes two elements. One is a rigid preformed angle having first and second legs generally at right angles to one another. The first leg is bendable into an annulus during assembly of the core protector. The second leg has a plurality of spaced cuts in it extending from the apex of the angle to the outer edge thereof. These cuts permit bending of the angle to conform to the inner diameter of the core with the spacing between each cut increasing or opening up as the angle is bent into an annulus. The other member is an annular retainer disk having an inner diameter, an outer diameter, and an intermediate diameter therebetween defining an annular fold line equal in diameter substantially to the diameter of the annulus formed by the preformed angle. The disk has a plurality of spaced cuts therein extending from the inner diameter to the intermediate diameter and is receivable on the first leg of the angle when it is bent into an annulus. On assembly, the material between the spaced cuts in the disk are folded 90.degree. and lie against the first leg of the angle. The remaining material between the intermediate diameter and outer diameter in turn lies against the second leg of the angle so that when the interior core protector is positioned in a core of material the space between each cut in the second leg of the angle is covered by the disk, and the spaces between each cut in the disk is covered by the first leg of the angle to provide complete protection for the coil of material around substantially the entire circumference of the coil. The annular retainer disk serves to firmly position the preformed angle annulus in place.
Preferably the preformed angle is formed of multiple plies of paperboard that are laminated, glued, treated, and formed into a rigid right angle. The annular retaining disk is preferably formed of double-walled corrugated. In packaging and shipping, the preformed angles are stacked one upon another and shipped in a straight or non-arcuate condition. Likewise, the annular retaining disks are stacked upon one another and shipped in a flat stacked condition. The core protector can be quickly and easily assembled at the customer's site by bending the preformed angle into an annulus and inserting it into the retaining disk whereupon the preformed angle expands the segments of the retaining disk between the inner diameter and intermediate diameter and forces them to a position perpendicular to the remainder of the disk.
Thus, the present invention provides a rigid interior core protector which is economically manufactured and economically packaged and shipped.